Introduction
In the study of liquid mixtures, volume contraction occurs when the total volume of the mixture is less than the sum of the volumes of the individual components. This phenomenon is often due to the interactions between molecules that lead to a more compact arrangement.
Explanation of Volume Contraction
When two liquids are mixed, the extent of volume contraction depends on the nature of the liquids and their molecular interactions. In the case of the mixture of acetone and aniline (option B), the following factors contribute to contraction:
Molecular Interactions
- Hydrogen Bonding: Aniline contains an amino group (-NH2) capable of forming hydrogen bonds. When mixed with acetone, which can act as a hydrogen bond acceptor due to its carbonyl group, strong intermolecular interactions occur.
- Change in Structure: The formation of hydrogen bonds between acetone and aniline leads to a more compact structure as the molecules fit more closely together than they do individually.
Comparison with Other Mixtures
- Methanol + Water: This mixture shows some contraction due to hydrogen bonding, but it does not result in significant volume reduction compared to acetone and aniline.
- Acetone + Benzene: These two liquids do not have strong intermolecular interactions, leading to little or no contraction.
- Acetone + Carbon Disulfide: Similar to acetone and benzene, there is minimal interaction, resulting in negligible volume contraction.
Conclusion
The contraction in volume observed in the acetone and aniline mixture is primarily due to strong hydrogen bonding and favorable molecular interactions that lead to a denser arrangement of the molecules. This makes option B the correct answer when considering which liquid mixture shows contraction in volume.

Acetone and aniline mixture show negative deviation.